Implantable electrical stimulators may be used to deliver electrical stimulation therapy to patients to treat a variety of symptoms or conditions such as chronic pain, tremor, Parkinson's disease, epilepsy, urinary or fecal incontinence, sexual dysfunction, obesity, or gastroparesis. In general, an implantable stimulator delivers neurostimulation therapy in the form of electrical pulses. An implantable stimulator may deliver neurostimulation therapy via one or more leads that include electrodes located proximate to target tissues of the brain, the spinal cord, pelvic nerves, peripheral nerves, or the stomach of a patient. Hence, stimulation may be used in different therapeutic applications, such as deep brain stimulation (DBS), spinal cord stimulation (SCS), pelvic stimulation, gastric stimulation, or peripheral nerve stimulation. Stimulation also may be used for muscle stimulation, e.g., functional electrical stimulation (FES) to promote muscle movement or prevent atrophy.
Implantable medical leads carry electrodes that may be used to deliver electrical stimulation and/or sense electrical physiological signals. Different examples of implantable medical leads include cylindrical leads carrying ring electrodes or segmented electrodes and paddle style leads that carry electrode contacts. Paddle style leads may provide directional stimulation, but often require surgical implantation, although percutaneous implantation is possible. Cylindrical leads with ring or segmented electrodes may be implanted surgically or percutaneously.
In general, implantable medical leads include one or more electrodes at or near a distal end of the lead, e.g., on a distal portion of the lead, which may be positioned proximate the patient tissue to be stimulated and/or from which the physiological signals are to be sensed. Implantable medical leads also include one or more connectors at or near a proximal end of the lead, e.g., on a proximal portion of the lead. The connectors are electrically connected to a respective one or more of the electrodes by one or more conductors within the body of the lead. The connectors may be electrically connected to circuitry within an implantable medical device, e.g., via a header of the implantable medical device and, in some cases, via a lead extension. In some cases, the proximal portion of the lead, including the connectors, may be inserted into a receptacle of the header or lead extension to mechanically and electrically connect the lead to the implantable medical device.